METHOD FOR THE NON-LEACHABLE IMMOBILISATION OF MOLYBDENUM COMPOUNDS IN A SLAG

摘要

The invention relates to a method for the non-leachable immobilisation of molybdenum compounds in a slag by treating iron- and molybdenum-containing waste streams under reducing conditions, for example under an oxygen pressure of 10-6 to 10-12 bar, advantageously 10-7.5 to 10-9.5 bar, at a temperature which advantageously is 50 DEG C above the liquidus temperature of the slag and under a thermodynamic activity of Fe(II) in the slag of more than 0.5, the Fe(III)/Fe(II) ratio in the slag being adjusted to a value of between 0.25 and 2. The resulting slag is then cooled in such a way that a solid solution of MoO2 in a spinel structure is obtained, which spinel structure exhibits a very low leaching value for molybdenum. By reason of this, such slags can be used, for example, as material in the construction industry.